Outdoor weatherable plastic siding panels made from vinyl (polyvinylchloride or PVC) are extensively used in a wide range of buildings and throughout the construction industry. Wood, metal, and vinyl are materials commonly used as boards or shingles for siding in the construction and remodeling of commercial and residential structures. Painted wood is perhaps the most aesthetically pleasing of these materials to the consumer, but wood suffers from deterioration by rotting and attack by insects, rodents and birds. Wood surfaces need constant reprotection with paint, stains and water sealants.
Advantages of metal over wood include the ability to provide a baked-on finish that is more resistant to the elements than coatings applied to wood, which eliminates subsequent material and labor costs to the consumer. However, metal-based siding has less thermal insulation value and is sensitive to scratching and denting by hail and other blows to the surface. In addition, it does not have the pleasing look of a wood surface.
Despite the economical advantages of vinyl siding over most high quality wood and metal siding, vinyl may suffer from degradation from ultraviolet and infrared rays of the sun. Such degradation causes heat buildup, which results in warping, bowing, and oil canning of the vinyl siding.
Commercial vinyl siding is typically made by a process in which an extruded plastic sheet, e.g., PVC, has been layered with a clear coat known for its adhesive properties, one or two wood grain print coats, and a top coat. Currently, a color coat, e.g., a print coat to help give the appearance of wood grain, includes a pigment material to protect the plastic sheet from UV degradation. U.S. Pat. No. 5,284,693, for example, describes employing “dark pigments” in the print layers to prevent heat build. Yet, there still exists substantial heat build up in the vinyl from the sun. Thus, there is a need for decorative panel sheets with sufficiently low heat build up.